Difference between CNS & PNS | Biology for JAMB PDF Download

Introduction

The nervous system is a complex network of specialized cells that coordinates and controls the activities of the body. It is divided into two main parts: the Central Nervous System (CNS) and the Peripheral Nervous System (PNS). Each system has distinct functions and characteristics. In this note, we will discuss the key differences between the CNS and PNS, according to JAMB Biology.

Central Nervous System (CNS)

• Definition: The CNS consists of the brain and the spinal cord.
• Location: It is located within the axial skeleton, which includes the skull and vertebral column.
• Function: The CNS is responsible for integrating and processing information received from the sensory organs and sending appropriate motor responses.
• Brain: The brain is the control center of the body and is responsible for complex functions such as thoughts, emotions, memory, and voluntary movements.
• Spinal Cord: The spinal cord acts as a communication pathway between the brain and the PNS. It also coordinates reflex actions, which are rapid responses to stimuli that do not involve conscious thought.

Peripheral Nervous System (PNS)

• Definition: The PNS consists of all the nerves outside the CNS, including the cranial nerves and spinal nerves.
• Location: It extends from the CNS to the extremities of the body.
• Function: The PNS transmits sensory information from the body to the CNS and carries motor commands from the CNS to the muscles and glands.
• Cranial Nerves: These are the nerves that emerge from the brain and primarily control functions related to the head and neck.
• Spinal Nerves: These nerves originate from the spinal cord and are responsible for transmitting signals to and from the rest of the body.

Key Differences between CNS and PNS

• Structure: The CNS consists of the brain and spinal cord, whereas the PNS includes all the nerves outside the CNS.
• Location: The CNS is located within the axial skeleton, while the PNS extends throughout the body.
• Function: The CNS integrates and processes information, whereas the PNS transmits sensory information and motor commands.
• Complexity: The CNS performs more complex functions such as thoughts, emotions, and memory, while the PNS primarily handles basic sensory and motor functions.
• Components: The CNS comprises the brain and spinal cord, while the PNS consists of cranial nerves and spinal nerves.

Conclusion

The CNS and PNS are integral parts of the nervous system, with distinct functions and structures. The CNS, consisting of the brain and spinal cord, performs complex integration and processing tasks. On the other hand, the PNS, including cranial and spinal nerves, transmits sensory information to the CNS and carries motor commands to the muscles and glands. Understanding the differences between these two systems is crucial for comprehending the overall functioning of the human nervous system.